The field of this invention relates to valves for fluid conduits and more particularly to a valve which is to be automatically movable to a postion blocking the flow of fluid through a fluid conduit upon the valve incurring a jarring force of sufficient magnitude such as what would occur by an earthquake.
It is well-known that certain geographical areas are subject to frequent earthquakes. Within these areas are many residences and businesses. It is common that most of these residences and businesses are supplied with an inflammable gas which is utilized within the residences and businesses to operate a water heater, a stove, a clothes dryer or other similar type of appliance.
It is a common occurrence that, if the gas line incurs a sufficient force, rupture of the line will occur. The rupture of the line will result in flooding of the entire area with inflammable gas. Not only is this gas toxic to any individual that may be caused to breath such for an extended period of time, but most importantly it is easily combustible and almost always results in an explosion which produces a fire and results in destruction of the residence or place of business.
Previously, there have been many attempts of designing valves which are to be incorporated with a gas line to automatically shut the gas line off in the event of an earthquake. One common type of such a valve is what is shown within U.S. Pat. No. 4,535,796 which utilizes a severable link which is to break upon a sufficient force being encountered resulting in a valve plug being moved to a fluid flow blocking position. The inherent disadvantage of this type of device is that this valve is not easily resettable and actually requires replacement of the severable link in order for the valve to be moved to a resetting position. Another way such valves have been known to operate is through the use of a spring actuated latching mechanism which, when jarred, will disengage permitting the valve to move to a blocking position. Such resettable latch type mechanisms are shown by U.S. Pat. Nos. 4,103,697 and 4,513,763. A third type of an earthquake actuated shut-off valve utilizes a weight which, when jarred with sufficient force, is caused to move to a different position which then permits the valve to move to a closing position. Such an inertial weight activated valve is shown and described within U.S. Pat. Nos. 2,158,753 and 4,131,124.
Also, a common disadvantage of all of the aforementioned Patents is that they are complicated and, therefore, inherently expensive to manufacture and to sell to the consumer. Also, a disadvantage of such prior art mechanisms have been that they must remain in an activatable position for an extended period of time and not be affected by deterioration due to the extended period of non-usage. It is common that after such an extended period of inactivity that shut-off valves of the prior art do not function when needed. Also, a prior art device can be adjusted to shut-off upon incurring of an earthquake of a certain magnitude. However, after a period of time a substantially greater magnitude of earthquake is required in order to effect operation of the valve.